While the damage and casualties in Japan are still being assessed, one bit of good news concerning the events in that country is that one key piece of infrastructure has managed to stay up and running despite the massive earthquake and tsunami waves: The Internet.

The folks at Internet research firm Renesys, who first gained attention for tracking Egypt's disconnection from the Internet, and then similar events in Libya, say they're surprised by how little the quakes have affected the undersea Internet cables that keep Japan connected to the rest of the world. Only a small fraction of Japanese connections went down, and many of those have come back up since. This is good news because the Internet is providing a badly needed communication link both within Japan and between it and the rest of the world.

It's a much different story from the Taiwan earthquake in 2006 that broke several undersea cables and knocked several carriers out of service.

That's not to say there hasn't been damage. There have been breaks in two segments of Pacnet's EAC cable system. And the Pacific Crossing system has also gone down since the earthquake. This is the cable once featured in a Wired photo essay "Tracing the Journey of a Single Bit." The Pacific Crossing site currently displays a message that reads: "The Japanese cable landing station in Ajigaura has been evacuated due to the tsunami on the east coast of Japan and currently information on restoration activities and timing is unavailable. Further updates will be posted as additional information becomes available."

Meanwhile, I've been keeping track of all the aftershocks--and there have an alarming number of them--via the Earthquake Notification Service operated by the U.S. Geological Survey. Subscribe and you get an automated e-mail alert any time there's an earthquake anywhere in the world, though you can specify by region and by the Richter Scale intensity so your in box isn't overloaded. For example I get alerts on North American quakes of greater than Richter 5.5, and all quakes around the world greater than Richter 6.5. When a big quake hits you'll know about it well before the cable networks start flashing their "Breaking News" banners.

Finally, you can keep up with the constant stream of updates out of the Japan via this ongoing blog from our friends at The Wall Street Journal.